To achieve high efficiency in the polishing process to obtain a high surface quality of black LT substrate (a kind of soft brittle material), shear thickening polishing (STP),which is a “gentle” finishing process developed in recent years, was employed in this study. The influence of three key parameters in the STP process including polishing speed, diamond abrasive size and diamond abrasive concentration were analyzed. To investigate the potential mechanical effect of the nanometre abrasive, nano-SiO₂ abrasive particles were added in the slurry, and the concentration of SiO₂ abrasive was also taken as a factor. Taguchi method was utilized to evaluate the influence of the four factors and optimize the polishing conditions. The surface roughness (Ra/Rz) was used as the evaluation index, and the optimized polishing conditions were verified through experiments. Diamond abrasive size has the most significant effect on Ra/Rz, followed by diamond abrasive concentration and then SiO₂ concentration, as the polishing speed has been selected and limited in a small variation rang according to the previous study. Based on the S/N average response analysis, the surface quality is the best under the conditions with 8000# diamond abrasive, 5 wt% diamond abrasive concentration, 90 rpm polishing speed and 10 wt% SiO₂ concentration. After 4 min polishing, the surface roughness Ra/Rz is reduced rapidly from 200.5/1374.6 to 4.2/22.1 nm without embedded abrasive particles on the surface of the black LT substrate. It also shows that the mechanical effect plays a dominant role in the material removal. A certain amount (10 wt% in this study) of nano-SiO₂ can reduce friction between solid colloidal and workpiece, and helps to improve surface quality.

为了在抛光过程中获得高效率以获得黑色LT基板（一种软性脆性材料）的高表面质量，最近采用了剪切增稠抛光（STP），这是近年来开发的“柔和”精加工工艺。这项研究。分析了STP工艺中三个关键参数的影响，包括抛光速度，金刚石磨料尺寸和金刚石磨料浓度。为了研究纳米磨料的潜在机械作用，在浆料中添加了纳米SiO ₂磨料颗粒，并且还考虑了SiO ₂磨料的浓度。Taguchi方法用于评估这四个因素的影响并优化抛光条件。表面粗糙度（Ra / Rz）作为评价指标，并通过实验验证了优化的抛光条件。金刚石磨料尺寸对Ra / Rz的影响最大，其次是金刚石磨料浓度，然后是SiO ₂浓度，因为根据先前的研究已选择了抛光速度并将其限制在很小的变化范围内。根据信噪比平均响应分析，在8000＃金刚石磨料，5 wt％金刚石磨料浓度，90 rpm抛光速度和10 wt％SiO ₂浓度的条件下，表面质量最佳。抛光4分钟后，表面粗糙度Ra / Rz迅速从200.5 / 1374.6 nm减小到4.2 / 22.1 nm，而黑色LT基板表面没有嵌入磨料颗粒。这也表明机械作用在材料去除中起主要作用。一定量（本研究中为10 wt％）的纳米SiO ₂可以减少固体胶体与工件之间的摩擦，并有助于改善表面质量。